The present invention relates to a jig for positioning a press plate to be perforated by a punch press.
Heretofore, a photosensitive medium to be used in the printing industry is formed in advance with positioning holes or recesses which are of a shape suitable for a printing press, and then is set in a process camera with the holes or recesses being used as a positioning reference. Then, an image is photographed on the photosensitive medium. If the photosensitive medium is a direct press plate, then the image photographed thereon is developed and the photosensitive medium is completed as a press plate. If the photosensitive medium is not a direct press plate, then page make-up is done with the holes or recesses being used as a positioning reference, and a press plate is produced from the photosensitive medium by close contact exposure in a printer. Then, the press plate is set in the printing press while using the holes or recesses as a positioning reference. In this manner, a printed document of good finishing accuracy can be produced by the printing press in either a monochromatic printing mode or a multicolor printing mode which is free of color misalignment.
There have been used in the art process cameras which are capable of successively photographing multiple-page copy images on one photosensitive medium. One example of such process camera is disclosed in Japanese patent application No. 63-122543. According to the disclosed process camera, reference holes or recesses are formed in a press plate with reference to the positions of photographed images with in the process camera. However, the reference holes or recesses thus formed in the process camera may not necessarily be of a shape and position suitable for a printing press that will be employed in the printing process. Therefore, the press plate may not be set in the printing press while using the reference holes or recesses as a positioning reference. Since the reference holes or recesses are formed with reference to the positions of the photographed images, however, it should be possible to define holes or recesses matching the printing press to be used, by using the reference holes or recesses as a positioning reference.